entirely refute the conclusion. The various forms of which a species 
is composed within the same locality, however different they may 
appear, are not incipient species and will never become inde- 
pendent of each other as long as they exist side by side in the same 
district. There are two criteria of specific distinctness which admit 
of demonstration. Firstly, 1f two distinct species are crossed, they 
produce intermediates; individuals so sharply separated as mima 
and wahlbergi do not produce intermediates when crossed. 
Secondly, distinct species as a rule are morphologically distin- 
guished by certain differences in the reproductive organs. In the 
species of Amauris, Planema, etc., which we have figured such 
differences are found, whereas nothing of the kind is observed in 
the individual forms of //yfolimnas, Pseudacrea, etc. In fact, 
systematists have not come across a single case of individual forms 
of di- or polymorphic species exhibiting even rudiments of such 
distinctions (1). 
If we wish to find rudimentary species, systematics tell us to 
turn our attention to those varieties which exist under different 
environments. The geographical races of Lepidoptera conform to 
the above criteria of specific distinctness in a lesser degree than 
species. They are the incipient species, and their systematics 
present us with all degrees of distinctness, from the mere slight 
shifting of the average to geographical forms which have all the 
morphological characteristics of species. 
(1) There exists a slight difference in the Q' genitalia of the seasonal forms 
of Papilio xuthus. 

